Copyright

© ANPEC Electronics Corp.

Rev. A.2 - Aug., 2009

APW7158

www.anpec.com.tw

1

ANPEC reserves the right to make changes to improve reliability or manufacturability without notice, and

advise customers to obtain the latest version of relevant information to verify before placing orders.

Dual Synchronous Buck PWM Controllers

The APW7158 has two synchronous buck PWM control-

lers with high precision internal references voltage to of-

fer accurate outputs. The PWM controllers are designed

to drive two N-channel MOSFETs in synchronous buck

topology. The device requires 12V and 5V power supplies.

If the 5V supply is not available, the device can offer an

optional shunt regulator 5.8V for 5V supply.

Both outputs have independent soft-start and enable func-

tions combined on the SS/EN pin. Connecting a capaci-

tor from each SS/EN pin to the ground for setting the soft-

start time, and pulling the SS/EN pin voltage below 1V to

disable regulator. The device also offers 180

function between OUT1 and OUT2.

The default switching frequency is 300kHz (keep the FS

pin open or short to GND), and the device also provides

the programmable switching frequency function to ad-

just the switching frequency from 70kHz to 800kHz. Con-

necting a resistor from FS pin to GND increases the

switching frequency. Conversely, connecting a resistor

from FS pin to VCC12 decreases the switching frequency.

There is no current sensing or under-voltage sensing on

the APW7158. However, it provides a simple short-circuit

protection by monitoring the COMP1 pin and COMP2 pin

for over-voltage. When any of two pins exceed their trip

point and the condition keeps for 1-2 internal clock cycles

(3-6us at 300kHz), all regulators are latched off.

Features

•

Two Synchronous Buck Converters(OUT1,OUT2)

•

Converter Input Voltage Range up to 12V

•

0.6V Reference for OUT1 with 0.8% Accuracy

•

3.3V Reference for OUT2 with 0.8% Accuracy

•

Both Outputs have Independent Soft-Start and

Enable Functions

•

Internal 300kHz Oscillator and Programmable

Frequency Range from 70 kHz to 800kHz

•

180 Degrees Phase Shift etween OUT1 and OUT2

•

Short-Circuit Protection

•

Thermally Enhanced SOP-20 Package

•

Lead Free and Green Devices Available

(RoHS Compliant)

Applications

General Description

•

Graphic Cards

•

Low-Voltage Distributed Power Supplies

•

SMPS Application

Simplified Application Circuit

Pin Configuration

FB1 1

COMP1 2

COMP2 3

FB2 4

REFIN 5

REFOUT 6

SS1/EN1 7

SS2/EN2 8

VREF 9

FS10

20 VCC

19 BOOT1

18 UGATE1

17 VCC12

16 LGATE1

15 LGATE2

14 PGND

13 BOOT2

12 UGATE2

11 GND

S

APW7158

V

OUT1

REFIN

REFOUT

SS1/EN1

VCC12

VCC

V

IN1

V

IN2

V

OUT2

V

OUT1

V

OUT2

SS2/EN2